The CPU Internal Error (CPU IErr) or CPU Machine Check error is usually not an error of the CPU itself, but a sign that the CPU has detected an error in the system, or received an erroneous instruction from a system component. This can theoretically be caused by any system component, but it is often caused by a memory error.

If any other errors are identified, resolve these errors. How to resolve the errors would depend on the error identified.

If no errors are found, or the CPU IErr remains, shut down the system, remove the power cable and hold in the server power button for 20 seconds before plugging the power cable back and turning the system on again.

Clear System Event log. i.e. in Open Manage Server Administrator or iDRAC (for both, open the event log, scroll to the bottom and press clear log)

Update the BIOS and iDRAC firmware to the latest version.
- How to update the BIOS or the iDRAC using the iDRAC interface is explained in this article.
- If the iDRAC is not available, other update methods are listed in the following tutorial article.